Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
|
experiments prove |
cause and effect |
|
|
retrospective observational study |
Subjects are selected and then their previous conditions or behaviors are determined |
|
|
prospective observational study |
subjects are followed to observe future outcomes |
|
|
observational study |
a study based on data in which no manipulation of factors has been employed |
|
|
random assignment |
to be valid, an experiment must assign experimental units to treatment groups at random |
|
|
factor |
a variable whose levels are controlled by the experimenter |
|
|
response |
a variable whose values are compared across different treatments |
|
|
experimental units |
individuals on whom an experiment is performed (subjects, participants) |
|
|
level |
the specific values that the experimenter chooses for a factor |
|
|
treatment |
the process, intervention, or other controlled circumstance applies to randomly assigned experimental units |
|
|
control |
aspects of the experiment that we know may have an effect on the response, but that are not factors being studied |
|
|
randomize |
subjects to treatment to even out effects that we cannot control |
|
|
replicate |
over as many subjects as possible. Results for a single subjects are just anecdotes |
|
|
block |
to reduce the effects of identifiable attributes of the subjects that cannot be controlled |
|
|
statistically significant |
when an observed difference is too large for us to believe that it is likely to have occurred naturally, we consider the difference statistically significant. |
|
|
blinding |
an individual associated with an experiment who is not aware of how subjects have been allocated to treatment groups is said to be blind |
|
|
completely randomized design |
all experimental units have an equal chance of receiving any treatment |
|
|
randomized block design |
the randomization occurs only within blocks |
|
|
matching |
in a retrospective or prospective study, subjects who are similar in ways not under study may be matched and then compared with each other on the variables of interest. Matching reduces unwanted variation |
|
|
blocking |
when groups of experimental units are similar, often a good idea to gather them together into blocks |
|
|
population |
the entire groups of individuals or instances about whom we hope to learn |
|
|
sample |
a representative subset of a population examined in hope of learning about the population |
|
|
sample survey |
a study that asks questions of a sample drawn from some population in the hope of learning something about the entire population. Polls taken to assess voter preferences are common sample surveys |
|
|
randomization |
the best defense against bias; each individual is given equal chance of selection |
|
|
sample size |
the number of individuals in a sample the sample size determines how well the sample represents the population, not the fraction of the population sampled |
|
|
census |
a sample that consists of the entire population |
|
|
population parameter |
a numerically valued attribute of a model for a population |
|
|
simple random sampling (SRS) |
a simple random sample of sample size n is one in which each set of n elements in the population has an equal chance of selection |
|
|
sampling frame |
a list of individuals from whom the sample is drawn is called the sampling frame |
